The 2016 Toyota Tacoma has undergone a complete redesign and is now more potent and efficient than ever. The Toyota Tacoma now features a bolder, more commanding platform that is matched with a more potent, more effective Atkinson cycle engine thanks to the total makeover. The Atkinson cycle engine, a cutting-edge piece of automotive technology, is a key element of the 2016 Toyota Prius design and other Toyota hybrid cars. As we explain what the Toyota Tacoma Atkinson cycle engine is, take a closer look at the new powerplant.
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How Do Toyota Atkinson Cycle Engines Work?
Standard Otto cycle engines run on a straightforward intake, compression, power, and exhaust sequence, which is enhanced when you use an Atkinson cycle engine. A second linkage is used in Atkinson cycle engines to enable the air intake valve to remain open for a longer period of time, resulting in a shorter and more complete compression stroke. This guarantees that the 3.5-liter Atkinson cycle V-6 engine in the new Tacoma will operate at its most powerful and efficient. Atkinson cycle engines are consequently 12 to 14 percent to 12 to 14 percent more efficient than a normal engine.
What advantages does an Atkinson cycle engine have?
James Atkinson, a British engineer, looked for ways to enhance the Otto four-stroke combustion engine, which was created for the first time in 1876, like countless other 19th-century inventors, businesspeople, and tinkerers. His 1882 invention for an engine included a multilink connecting rod between the piston and the flywheel that allowed for adjustable stroke lengths. Despite the failure of Atkinson’s engines, his thermodynamic cycle is still widely used, particularly in gas-electric hybrids. The main benefit is higher efficiency than is possible with an Otto engine, but with significant output reduction at low speeds. Because hybrids’ electric motor(s) make up for the lost low-speed output, the Atkinson cycle is the best choice.
Intake valve closure is postponed by the Atkinson cycle until the piston has made 20 to 30 percent of its upward ascent during the compression stroke. As a result, the cylinder is never fully charged since the rising piston forces some of the fresh charge back into the intake manifold (hence the low-speed power reduction). After ignition, the payout occurs when the piston starts to fall during the expansion (also known as power) stroke. According to Atkinson’s original reasoning, the combination of a short intake stroke and a long expansion stroke maximizes the amount of work that can be done with each unit of fuel.
In order to maximize power and efficiency, the compression ratio is often set as high as the engine can tolerate without detonating. In an Otto engine, the compression and expansion ratios are equal. Because Atkinson’s expansion ratio is far higher than its compression ratio, it performs more efficiently.
Which automobiles have Atkinson cycle engines?
Atkinson-cycle powered vehicles
- Volt by Chevrolet.
- Chrysler Pacifica plug-in hybrid minivan (front-wheel drive).
- Ford C-Max hybrid and plug-in hybrid vehicles (front-wheel drive; US market).
- Electric front- and four-wheel-drive Ford Escape/Mercury Mariner/Mazda Tribute vehicles have a compression ratio of 12.4:1.
What is a hybrid Atkinson cycle?
From an operational perspective, the Atkinson cycle is comparable to the Otto cycle. The intake valve opens, the exhaust valve closes, the piston lowers from the top of the cylinder, and fuel and air are driven into the cylinder during the first stroke. The pressure within the cylinder is at around one bar.
By how much is the Atkinson cycle more effective?
Toyota has announced the development of two extremely fuel-efficient small-displacement petrol Atkinson cycle engines: a three-cylinder 1.0-liter and a four-cylinder 1.3-liter. Both of these engines will be available across the range starting in 14 various configurations the following year. The Toyota Aygo will get 78 mpg (US) from the smaller engine, which is a 30% increase.
Particularly impressive is the one-liter engine’s fuel efficiency. From 2007 to 2010, the engine it will replace took first place in the One Liter category of the International Engine of the Year awards four times.
Just one month ago, the award-winning three-cylinder 1.0-liter engine was announced as the drivetrain for the new Aygo at this year’s Geneva Motor Show.
The reengineered engine underwent a number of modifications, including a higher 11.5:1 compression ratio, an improved combustion chamber design, decreased frictional losses, and a lighter cylinder head with an integrated exhaust manifold.
The updated unit will now be replaced once more with an Atkinson Cycle engine that was created in collaboration with Daihatsu and has the same three cylinder, 1.0-liter layout.
Atkinson Cycle engines aren’t recognized for their low- and mid-range torque, but Toyota believes it has addressed this issue with a variety of advancements. Although Toyota has utilized Atkinson Cycle engines in its hybrids before, this is the first time the Atkinson design will be employed as a stand-alone unit.
A reshaped intake port that creates a strong tumble flow (where the air-fuel mixture flows in a vertical swirl) inside the cylinder, a cooled Exhaust Gas Recirculation (EGR) system, Toyota’s Variable Valve Timing intelligent Electric (VVT-iE) technology, an idling-stop function, a high compression ratio, and various unnamed fuel consumption reduction technologies are some of these innovations.
The end result is a maximum thermal efficiency of 37% and an improvement in fuel efficiency of “about 30% over current automobiles,” which translates to a remarkable increase in mileage from 60 to 78 mpg (US).
The Toyota Aygo is mostly purchased for usage on narrow, crowded urban roads, and owners value the car for its performance at the gas station rather in the traffic light Grand Prix. The unit will significantly boost the appeal of the Aygo and other small Toyota automobiles.
By 2015, the Japanese manufacturer intends to release 14 variants of the 1.0-liter three-cylinder and its larger 1.3-liter four-cylinder sibling.
The larger 1.3-liter Atkinson cycle engine combines the same engine advancements and a high compression ratio (13.5) to attain a thermal efficiency of 38%. Although the 1.3-liter engine’s efficiency figures aren’t quite as impressive as the one-liter engine’s, they nevertheless represent a 15% increase in fuel efficiency over current automobiles.
An Atkinson cycle engine can it turbo?
The Atkinson is intended to have a short compression stroke and a longer combustion stroke, as was previously stated (by valve timing). This concept would actually be cancelled out by a turbo, adding extra compression during the compression stroke.
What’s the process of an Atkinson engine?
Gasoline is sprayed into the engine, where it powers the pistons before being ignited by the spark plug. Each cycle involves the piston moving four times: downward to suck in gasoline vapour, upward to compress it, downward when the vapour ignites and explodes, and upward to push out the exhaust. In the midst of this, valves open and close exactly at the appropriate moments to let gasoline in and exhaust out.
Use of the Atkinson cycle by Honda?
Honda Accord Hybrid 2020 With a best-in-class total system output of 212 horsepower*, the Accord’s two-motor hybrid system combines a 2.0-liter DOHC i-VTEC Atkinson-cycle engine with 40% thermal efficiency with an electric propulsion motor that cranks out 232 lb-ft of torque.
How does the contemporary Atkinson cycle function?
Four-stroke engines, which use two crankshaft revolutions as well as precise valve and ignition timing, have four distinct phases within a conventional Otto cycle. These phases are: 1) intake, 2) compression, 3) combustion, and 4) exhaust, as shown in the animation below. Every one is equivalent to a whole piston stroke inside the cylinder.
A downward piston stroke initiates the cycle by drawing vapourized fuel and air through the intake port and into the combustion chamber. This mixture is compressed to about one-tenth of its capacity during the upward stroke of the returning piston, at which point the spark plug ignites it. The piston is driven downward by this explosion, creating the engine’s thrust. The spent gases are expelled out the exhaust port during the cycle’s final return stroke, allowing the process to restart.
However, even though this very simple cycle generates a fair amount of power, it is not the most fuel-efficient way to produce power from a four-stroke piston engine. That distinction belongs to Atkinson cycle engines.
What distinguishes the Miller from the Atkinson cycle?
A Miller-cycle engine employs a supercharger or turbocharger to force air into the system, whereas an Atkinson-cycle engine uses natural aspiration. This is how an Atkinson-cycle engine differs from a Miller-cycle engine.
What cycle does a hybrid engine use?
The Atkinson Cycle is most frequently used by full hybrids. By shortening the intake and compression strokes, this four-cylinder engine’s operating cycle is intended to maximize efficiency at the sacrifice of output.
How is a heat engine put to use?
A heat engine is a sort of engine, similar to the car’s motor, that uses heat to create macroscopic motion. Rub your hands together to create friction, which converts the action of your hands’ mechanical energy into thermal energy (the hands get warmer). The exact opposite is accomplished by heat engines, which convert the energy from being heated relative to the environment into motion. A generator is frequently used to convert this motion into electricity.
Heat engines provide almost all of the energy that is used to generate electricity and power vehicles. Thermal energy can be converted into useable energy in hot substances, including gases. Heat engines convert some of the energy they transfer from a hot environment to a cool one into mechanical energy. For heat engines to work, there must be a temperature difference.
The pursuit of maximizing the energy output from heat engines served as the original impetus for the study of thermodynamics.
[2] Even now, a variety of fuels are used, including uranium, coal, and gasoline. These heat engines all continue to function within the constraints set by the second law of thermodynamics. This indicates that a gas is heated using a variety of fuels, and waste heat must be removed using a sizable cold reservoir. Waste heat frequently enters the sky or a sizable body of water (the ocean, a lake, or a river).
Different procedures are used depending on the type of engine, such as burning fuel through combustion (gasoline and coal) or generating heat from nuclear processes (uranium), but the ultimate result is always the same: converting the heat into work. The engine in an automobile is the most well-known example of a heat engine, but most power plants, including coal, natural gas, and nuclear, are also heat engines.
What purpose served the Otto engine?
Most forms of transportation use the Otto Cycle, which was crucial to the development of modern society. In particular, the Otto Cycle is used by the vast majority of modern cars to turn gasoline into motion.
What kind of an engine is the Miller cycle?
Traditional reciprocating internal combustion engines have four strokes, of which the compression and power strokes (high power flow from the crankshaft to the charge) can both be regarded as high-power strokes (high power flow from the combustion gases to crankshaft).
Compared to an Otto-cycle engine, the intake valve is left open for a longer period of time in the Miller cycle. The initial phase of the compression stroke, when the intake valve is open, and the end phase, when the intake valve is closed, are actually two discrete cycles. The so-called “fifth” stroke introduced by the Miller cycle is produced by this two-stage compression stroke. The charge is partially ejected back out through the still-open intake valve when the piston rises first during what is known as the compression stroke. Normally, a loss of power would follow from this loss of charge air. However, the Miller cycle makes up for this by using a supercharger. Due to its capacity to produce boost at very low engine speeds, positive-displacement (Roots or screw) superchargers are often required. Low-rpm power will suffer otherwise. If low rpm operation is not necessary, a turbocharger can also be employed for increased efficiency, or electric motors can be added.
The intake valve closes in the Miller-cycle engine when the piston has moved a specific distance above its bottom-most position, or roughly 20 to 30% of the entire piston movement during this upward stroke. Only then does the piston start compressing the fuel-air combination. The fuel-air combination is only actually compressed by the piston in the Miller cycle engine during the last 70% to 80% of the compression stroke. The piston forces some of the fuel-air mixture through the still-open intake valve and back into the intake manifold during the first phase of the compression stroke.